During an examination with a medical examination apparatus such as a computed tomography device (CT device), a radiation therapy device or a magnetic resonance device, the patient to be examined is situated in an examination area inside the medical examination apparatus. As a rule patients already find being examined a stressful experience. In addition, during the examination the temperature prevailing in the examination area often increases as a result of the examination and the patient's body heat. The patient generally finds this unpleasant and this increases the stress and unease that the patient experiences. Furthermore, the air in the examination area is normally still and therefore easily starts to feel oppressive and, the fact that the examination area frequently seems cramped contributes to this. This often leads to a patient becoming increasingly agitated.
Magnetic resonance technology (hereinafter the abbreviation MR is used to stand for magnetic resonance) is a known technique, by means of which images from inside an examination object can be produced. Simply expressed, the examination object is positioned in an MR unit in a comparatively strong, static, homogenous main magnetic field (field strengths from 0.2 Tesla to 7 Tesla and more) so that its nuclear spins are oriented along the main magnetic field. To trigger nuclear spin resonances, high frequency excitation pulses are radiated onto the object to be examined, the triggered nuclear spin resonances are measured and based on this, image and/or spectroscopy data of the examined object, for example, are reconstructed. For position coding of the measurement data rapidly switched magnetic gradient fields are quickly superimposed on the main magnetic field.
During an examination with a magnetic resonance device (MR examination), the temperature in the magnetic resonance device can increase in particular due to the high frequency alternating fields that have to be applied. Various factors have an influence on the temperature in an examination area, in particular in a magnetic tube, of the magnetic resonance device. Some of these factors are, for example, the main magnetic field strengths, the duration of the respective examination and the duration of an individual measurement, the examination sequence used, the room temperature surrounding the magnetic resonance device and also, of course, the patient himself/herself.
In order to prevent the patient from becoming too warm during an MR examination, generally an air flow is produced which is designed to cool the patient generally with the aid of a ventilator arranged at the entry or exit of the magnetic tube of a cylindrical magnetic resonance device or adjacent to an open magnetic resonance device. In such cases only the strength of the air flow produced by the ventilator can be varied and the ventilator may be switched off if required, so as to adapt to the patient's wishes and requirements.
This method is, however, often insufficient, for example, in preventing the patient from sweating which is unpleasant. In addition, the air flow cannot be optimally controlled which means that this often cannot reach as far as the examination center of the examination area of a medical examination apparatus. It is precisely there where the temperature increases the most during an examination. Therefore pauses during the examination may be necessary in which the patient is moved out of the medical examination apparatus until the temperature in the examination area has dropped again.